so started from my own drawing not the photo ref.
And then endless reference researching.
As you see in my concept thumbnail, I wanted to make it extreme shot
with exaggerated perspective.
But there was a mistake of perspective itself
(I should have got rid of ground plane for castle`s extreme view
since the eye level is at below ground)
and Jeff pointed out my excessive perspective disturbs photo realism.
My eyes aleady got used to seeing this distorted sketch
so I made new grid with simple 3D boxes in Max.